CVS commit: src/sys/arch/powerpc/include

["Rin Okuyama" <rin%netbsd.org@localhost>]

Module Name:    src
Committed By:   rin
Date:           Fri Feb 21 12:56:37 UTC 2020

Modified Files:
        src/sys/arch/powerpc/include: param.h

Log Message:
Reduce UPAGES from 2 to 1 for ibm4xx, which was originally 1 and bumped
to 2 in rev 1.29:

    http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/powerpc/include/param.h#rev1.29

Since page size is 16KB on ibm4xx, USPACE is still 16KB, which is the
same size as on other powerpc processors.

This avoids kernel crash described in PR kern/54994. Also, even if the
PR is resolved, fork(2) easily fails with ENOMEM if UPAGES is 2, which
requires physically contiguous pages for u-area. No bad side effect is
observed as far as I can see.

XXX
Even with this commit, kern/54994 still critically affects other archs
with __HAVE_CPU_UAREA_ROUTINES, i.e., alpha, mips, powerpc/{oea,booke},
and riscv.


To generate a diff of this commit:
cvs rdiff -u -r1.31 -r1.32 src/sys/arch/powerpc/include/param.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.